Optimized multi-party certified email protocols

Purpose – As a value-added service to deliver important data over the internet with guaranteed receipt for each successful delivery, certified email has been discussed for years and a number of research papers appeared in the literature. This paper aims to present two optimized multi-party certified email protocols. Design/methodology/approach – Reviews two existing email protocols and provides a modified version to overcome their security flaws and weaknesses. Extends the two-party protocol to a multi-party scenario. Findings – Both of the protocols have three major features. A sender could notify multiple recipients of the same information while only those recipients who acknowledged are able to get the information. Both the sender and the recipients can end a protocol run at any time without breach of fairness. The exchange protocols are optimized, each of which has only three steps, and the trusted third party will not be involved unless an exception (e.g. a network failure or a party’s misbehavior) occurs. Originality/value – Provides a focus on a value-added service – certified email.